Chewing gums generally include gum base, water-soluble sweeteners and flavoring. The water-soluble sweeteners usually include sucrose, dextrose, corn syrup and/or sodium or calcium saccharin or combinations thereof. The chewing gum is generally prepared by melting the gum base, mixing corn syrup or liquid sweetener for 3 to 5 minutes with the gum base followed by the addition of solid sweetener (for example, sugar) and flavor and mixing for 5 minutes. The chewing gum is removed from the kettle, rolled and cut to the desired shape.
In the above chewing gum, the corn syrup (which provides a substantial portion of the moisture in the gum) will be retained in the gum base as part of the oil or insoluble phase and the sucrose and/or other sweeteners will be incorporated in a water-soluble phase which is in simple admixture with the oil phase and might even be considered to be coated on the gum base. The result is that the gum base will protect the corn syrup as an internal phase thereby minimizing the amount of corn syrup on the surface of the gum (surface corn syrup causes the gum to sweat). However, due to the equilibrium relative humidity of the chewing gum, eventual migration of moisture of the corn syrup to the gum surface and subsequent loss of moisture through evaporation is unavoidable at equilibrium relative humidities below that of the gum. Reduction in moisture content of chewing gum leads to loss of flexibility which manifests itself in increased stiffness and brittleness. The latter phenomena is, of course, associated with stale or old chewing gum.
In accordance with the present invention, it has now been found that where a humectant material, such as sorbitol, is included in the chewing gum after the corn syrup or other aqueous softener or moisturizer, and sweetener have been added to the gum base, (so that the aqueous softener and humectant material are substantially isolated from each other), the equilibrium relative humidity of the chewing gum will be lowered so that the chewing gum will tend to lose moisture at a substantially slower rate than conventional chewing gum. The result is that the chewing gum of the invention prepared with the humectant material will have enhanced flexibility retention as well as good sweat resistance since the humectant and corn syrup have been isolated from each other.